This invention relates to an induction and injection system for a multi-valve engine and more particularly to an improved arrangement for adapting an existing engine to a split or tuned type of induction system.
It has been recognized that the performance of internal combustion engines can be significantly improved throughout their entire speed and load ranges if the induction is designed in such a way so as to function as a relatively small effective cross-sectional area system and one which generates turbulence under low speed low load conditions and which functions is a relatively unrestricted large effective cross-sectional area induction passage at high engine running speeds and loads. This type of system is frequently used in conjunction with engines having two intake valves per cylinder because such an arrangement lends itself to this type of tuning.
Specifically, because of the placement of the twin intake valves, it is possible to disable the flow through one intake valve under some running conditions to generate swirl. Alternatively, it is possible to configure a control valve in the cylinder head in such a way that the flow through one or both passages can be redirected to generate a motion called tumble. Tumble is a type of swirl which acts around an axis that is perpendicular to the cylinder bore axis rather than parallel to it as with conventional types of swirl.
In order to improve the power output of an engine, it has been proposed to employ three intake valves per cylinder. Such three valve engines have the advantage of providing a larger effective flow area with reduced inertia than using two larger intake valves. However, the typical placement of the three intake valves makes it more difficult to obtain the types of swirl or turbulence within the combustion chamber that has been found to be effective. It has been determined, however, that by redesigning the configuration of the cylinder head to incorporate control valves therein that three valves per engine combustion chambers can utilize the advantages of such type of tuned induction systems. However, there are many engines which have been designed without these concepts and in which it would be desirable to employ them.
It is, therefore, a principle object of this invention to provide an improved induction and injection system for an internal combustion engine wherein a conventional engine can be modified so as to include flow control and fuel injection arrangements wherein certain intake passages can be selectively disabled and/or the direction of the flow entering the combustion chamber can be significantly altered so as to generate tumble without necessitating redesign or reconstruction of the cylinder head.
It is a further object to this invention to provide an improved and simplified induction and injection system for a three valve cylinder engine wherein the desired flow characteristics can be selectively generated.